John Lighton Synge (March 23, 1897–March 30, 1995) was an Irish mathematician and physicist.

Background
Synge was appointed to the position of lecturer at Trinity College, and then accepted a position at the University of Toronto in 1920. From 1920 until 1925, Synge was an assistant professor of mathematics at the University of Toronto. He returned to Trinity College in 1925, where he was elected to a fellowship and was appointed to the chair of Natural Philosophy (the old name for Physics). He was a member of the Mathematical Society of America and the London Mathematical Society. He was treasurer of the Royal Irish Academy in 1929. He went back to Toronto in 1930. He was appointed Professor of Applied Mathematics and became Head of the Department of Applied Mathematics.
He spent some of 1939 at Princeton University, and in 1941, he was a visiting professor at Brown University. In 1943 he was appointed as Chairman of the Mathematics Department of Ohio State University. Three years later he became Head of the Mathematics Department of the Carnegie Institute of Technology in Pittsburgh, where John Nash was one of his students. He spent a short time as a ballistic mathematician in the US Air Force between 1944 and 1945.
He returned to Ireland in 1948, accepting the position of Senior Professor in the School of Theoretical Physics at the Dublin Institute for Advanced Studies. This school had been set up in 1940, and had several outstanding members, including Erwin Schrödinger (who contributed to quantum mechanics), who was also a Senior Professor.

Honours
He is described as a kind and generous man. He encouraged and inspired several generations of students. He will be remembered by them with gratitute, fondness, and the deepest respect. He is one of the few people who make mathematics do useful work for solids, liquids, gases, and space.
Synge was a keen cyclist, was passionately interested in sailing, and painted some very nice pictures, including a picture representing Schrödinger held in the hands of God, thinking of theories.
The John L. Synge Award was established by the Royal Society of Canada, in 1986, to honour John Lighton Synge, one of the first mathematicians working in Canada to be internationally recognised for his research in mathematics. He was a member of the Royal Irish Academy, and was at the University of Toronto, and later a senior Professor at the Dublin Institute for Advanced Studies.